When adding an inbound service to the Communication Scenario, I'm getting some of the SAP Inbound Services listed double.
If checking one of the services and trying to activate via right-click, the duplicate appears as automatically checked too,
the message "Instance with the same key already exists" pops up and the scenario is not activated.
To solve this you should manually uncheck the duplicate inbound service and do the activation by pressing "Save and activate" button for the current document: